suggested at http://www.alsa-project.org/main/index.php/SoundcardTesting, for testing 5.1 output, makes a sound plays forever until reboot.
Other symptoms:
The sound is slow and like if you are in a tunnel with an echo, delayed. I am also still having choppy video problems. I made any kind of changes but none helped.
Any sound played starts to play and then keeps playing that first little part, sometimes forever until I close the application, be this a game such as Lagno, a .wav song, a video, the very login sound, or whatever.
The sound problem makes videos to play too slow, extremely slow, in Totem. A time I could play them right in VLC by setting VLC's audio to alsa instead of pulseaudio, I think (don't remember), but then I had no sound.
I've tried Ubuntu 7.10, 8.10 and 9. No progress. There is no solution for this issue.